NSTM 600 covers which category?

• A. Non-structural closures
• B. Structural closures
• C. Piping systems
• D. Electrical enclosures

Answer: (A)

NSTM 600 is about non-structural closures. In ships, closures are devices that seal openings, like doors, hatches, scuttles, and access covers. When we say non-structural, we mean closures that do not contribute to the hull’s structural strength or to the watertight integrity of the hull. This volume covers the maintenance, inspection, installation standards, and performance of these closures—how they should seal, how they’re hinged or operated, corrosion protection, hardware, and recommended service intervals. The goal is reliable operation and proper sealing in spaces where the closure doesn’t bear hull loads, which is why it’s categorized separately from structural closures (which deal with hull integrity) and from topics like piping systems or electrical enclosures that belong to other volumes.